Razorock F-400 Synthetic. Another very large brush, 34MM knot, 65MM loft, 151MM total height. Loaded on puck for about 60 seconds and straight to lather bowl. This brush made enough lather for my 3 face and 3 head passes. Lathered 3 face passes without returning to bowl- next head shave I returned to bowl to refresh and reload brush and lathered 3 head passes without returning to bowl. What a great brush!!